1. Field of the Invention
The invention relates to a suspension mechanism for an optical image anti-shake device, by which the anti-shake strength of a lens module in the optical image anti-shake device can be increased to a degree that possible permanent deformation thereof can be avoided while in meeting an accidental fall.
2. Description of the Prior Art
Digital photography technology has been widely applied to most of the portable electronic devices such as the cellular phones. Various miniaturized techniques in the lens module are involved to make all these applications possible; in particular, the voice coil motor (VCM) technique. The VCM introduces a combination of coiled magnets and spring plates to drive a lens to move back and forth along a photo axis for image-capturing, so as to perform auto-zooming and/or auto-focusing of the lens module. Further, in this trend of demanding for devices capable of high-level photographing functions, photographic quality and various camera functions such as thousand pixels, anti-hand shake ability and so on are equipped to distinguish high-end camera from cost-down level.
In an optical system composed of a lens module and an image-compensation module, such as a camera system or a video recorder system, hand shake or some external situations usually occur to alter optical path so as to degrade the imaging upon the image-compensation module and further to obscure the formation of the images. A conventional resort to resolve this problem is to introduce a further compensation mechanism for overcoming possible shaking during the imaging. Such a compensation mechanism can be either digital or optical.
State of the art digital compensation mechanism is to analyze and process the digital imaging data capturing by the image-compensation module, so as to obtain a clearer digital image. Such a mechanism is also usually called as a digital anti-shake mechanism. On the other hand, the optical compensation mechanism, usually called as an optical anti-shake mechanism, is to add a shake-compensation module upon the lens module or the image-compensation module. Currently, most of the optical anti-shake mechanisms in the market are consisted of plenty complicated or cumbersome components and thus are usually complicatedly structured, difficultly assembled, expensive, and hard to be further miniaturized. Obviously, a further improvement upon such the anti-shake mechanism is definitely necessary.
Referring to FIG. 1, an optical compensation mechanism in accordance with the Japan Patent No. 2002-207148 is schematically shown. The optical compensation mechanism includes four flexible steel strings 400k-403k to sustain a lens unit 203k upon a circuit board 301k having a central image sensor 300k. The lens unit 203k further includes a lens 200k and a lens holder 202k. The lens unit 203k can be a zooming or a focusing lens module. The lens 200k centrally located in the lens unit 203k can move back and forth with respect to the lens holder 202k along an optical axis 201k. While in meeting a shake, a relative displacement between the lens unit 203k and the circuit board 301k would be generated. Then, through two relative displacement sensors 500k, 501k and a position sensor 503k, both the X-axial displacement and the Y-axial displacement between the lens unit 203k and the circuit board 301k can be transmitted to an anti-shake unit 504k. According to the axial displacements, the anti-shake unit 504k controls and drives a shift unit 502k to perform a corresponding compensation movement upon the lens unit 203k with respect to the circuit board 301k, such that obscure imaging due to the shake can be avoided in the image sensor 300k. 
Nevertheless, the aforesaid Japanese patent is only a conceptual disclosure aiming at obscure imaging by hand-shaking. Details carried to a real practice are yet to be elucidated. Contrarily, the present invention herein is to integrate the Japanese concept and the auto-focusing module to provide a reality design that can react to the X-axial and Y-axial bias and avoid a possible Z-axial (same along the optical axis) permanent (plastic) deformation of the lens unit 203k due to accidental falls; such that an enhanced anti-shake capability against accidental falls can be provided to the concerned optical system.